This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In this project we intend to develop non-invasive methods to quantitatively assess cerebral metabolism during functional activation. The hypothesis of this project is that brain functional activation alters cerebral gluramate turnover. The basis for this assumption is that the measurement of glutamate turnover reflects the rate of the tricarboxylic acid (TCA) cycle and thus the cerebral metabolic rate of oxygen (CMR02). Essential to their performance of these studies will be experimental control and measurement of serum glucose, and insulin concentrations using the techniques employed for glucose clamps.